Palaeogeographic maps of Moscovian and Artinskian; contributions from the Netherlands

Mark GELUK Rijks Geologische Dienst, P. O. Box 157

2000AD Haarlem (The Netherlands)

Geluk M. 1997. — Palaeogeographic maps of Moscovian and Artinskian; contributions from the Netherlands, in Crasquin-Soleau S. & De Wever P. (eds), Peri-Tethys: stratigraphie cor­relations, Geodiversitas 19 (2) : 229-234.

K E Y W O R D S Westphalian,

Stephanian, Lower Rotliegende,

Variscan front, basins,

tectofacies.

ABSTRACT Frequent marine bands in the eatly Westphalian of the Nethetlands are replaced by peat matshes followed upwards by a braided-river/fluvial-plain system in the late Westphalian-Stephanian. Sediments are limited to the depocentets Stephanian. Asselian to Artinskian deposits ate tepresented by Lower Rotliegende volcanoclastics, basaltic volcanics and sediments of conti­

nental environment.

M O T S C L E S Westphalien,

Stéphanien, Rotliegende inférieur,

front varisque, bassins,

tectofacies.

RÉSUMÉ De nombreux niveaux marins du Westphalien inférieur des Pays-Bas sont remplacés vers le haut par des tourbes marécageuses suivies par des systèmes fluviátiles de plaine deltaïque au Westphalien supétieut-Stephanien. Les sédi­ments stéphaniens sont limités aux dépôts-centres. Les niveaux de l'Asselien à l'Artinskien sont représentés par des volcanoclastites du Rotliegende Inférieur, des basaltes et des sédiments d'environnement continental.

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Geluk M.

MOSCOVIAN TO GZHELIAN

The Moscovian deposits are represented, accor­ding to the current ideas, by approximately the interval of the Westphal ian C to Stephanian. The constraint is provided by the age dating of Lippolt et al. (1984) , which revealed an age of 311 M a for the base of the Westphalian C. The exact chronostratigraphic position of the youn­gest sed iments (? S tephan ian ) in the eastern Netherlands and adjacent part of Germany is still debated, since the pa lynologica l assemblages clearly indicate a younger age (Autunian) than the paleobotanical assemblages (Westphalian D; Van der Zwan et al. 1993). There is a tendency in G e r m a n y to place these sed iments in the youngest part of the Carboniferous, the Gzhelian (Plein 1995). During the Moscovian, an impor­tant change in climate occurred from humid tro­pical condi t ions to a (semi-) ar id c l imate , as documented by a change in soil type (Selter 1989; Van der Zwan et al. 1993).

In b r o a d t e r m s , the d e v e l o p m e n t of the Westphalian C to Stephanian deposits is quite s imilar throughout the onshore and offshore areas; the main difference consists of the amount of later erosion of the Carboniferous. For the Nether lands , one reference sect ion has been compiled for the eastern Netherlands (Fig. 1).

The present-day outline of the Moscovian depo­sits (Fig. 2) in the Netherlands is mainly control­led by erosion and uplift owing to the Variscan d e f o r m a t i o n phase d u r i n g the y o u n g e s t Carboniferous. In large part of the Netherlands onshore and western offshore areas Bashkirian (Westfalian A/B) deposits underlie the Permian rocks. Compared to the Westphalian A and B, the younger Westphalian and Stephanian have been deposited under increasing tectonic instabi­lity as the Variscan front prograded northwatd. This resulted in the intermittent tectonic activity of m a i n faul t zones , a n d at the e n d of the Carboniferous led to the deformation of the fore­land-basin infill. The Variscan phase is conside­red to have a c c e n t u a t e d the d i f fe rences in subsidence during the Moscovian. In the basins, up to 1200 m of Westphalian C to Stephanian

sediments have been preserved; in the uplifted areas, sediment thicknesses of this interval were probably not over 750 m and presumably consist of fine-grained sediments.

At the onset of the Westphalian C, extensive peat marshes existed over the entire Netherlands off­shore and onshore areas. Mar ine bands, which frequently occurred in the Westphalian A and B, o c c u r e d o n l y s p o r a d i c a l l y in the Ea r ly Westphalian C. During the late Westphalian C, owing to an abrupt influx of coarser gra ined sediments, these marshes were replaced by an extensive b ra ided - r ive r / f l uv i a l -p l a in sys tem. Sediments came basically from three different source areas, the Rhenish Massif in Germany in the southeast, the M i d North Sea High in the nor th , and the Brabant Mass i f to the south (Fig. 2) . Thete are minor differences in the onset and duration of these sandy influxes between the different parts of the basin. These sandy sediments were replaced in the early Westphalian D again by fine-grained sedimentation. The only exception is formed by the Campine Basin in north-eastern Be lg ium and the south-eastern Nether lands , where the sandy fluvial deposits are limited to the ear ly Wes tpha l i an D interval (Paproth et al. 1983). In other areas, during the Westphalian D deposition took place on a semi-arid flood-plain with sheet floods and braided rivers. Soil types indicate that these flood-plains became better drained during this timespan.

The occurrence of the ? Stephanian deposits is l imi ted to the depocentres of the Moscovian basins in the eastern Netherlands and probably the nor thern Ne the r l ands offshore area . An unconformable contact of the Stephanian with the underlying Westphalian D sediments is assumed (Tan tow 1 9 9 3 ; Van A d r i c h e m , Boogae r t & Kouwe 1993-1996). Stephanian deposits are for­med by well-drained distal floodplain deposits, w i th minor bra ided channels (Van der Zwan 1993).

ASSELIAN TO ARTINSKIAN

T h e Asse l i an to A r t i n s k i a n depos i t s in the

230 GEODIVERSITAS • 1997 • 19(2)

Palaeogeographic maps of Moscovian and Artinskian

52° 40 N 7° E

Ages according to Odin (1994), Lippolt et al. (1984}

Marine stages

Kungurian

Ghelian

Continental stages

Stephanian

Westph. D

Westph. C

Westph. A/B

Lithology

^1

Thickness

Rijks G e o l o g i s c h e Dienst r g d

FIG. 1 . — Reference columnar section for eastern Netherlands. See Vai & Venturini (this volume) for legend.

GEODIVERSITAS • 1997 • 19(2) 231

Geluk M.

M o s c o v i a n t o G z e l i a n

i 1 1 1 r 3°E 4°E 5°E 6°E 7°E

Rijks Geologische Dienst rgd

FIG. 2. — Deposits of Moscovian age in the Netherlands. See Vai & Venturlni (this volume) for legend.

GEODIVERSITAS • 1997 • 19(2)

Palaeogeographic maps of Moscovian and Artinskian

Asselian to Artinskian I I I I I r~

3'E 4"E 5'E 8'E 7'E

Ri jks G e o l o g i s c h e D i e n s t RGD

FIG. 3. — Lower Rotliegende volcanoclastlcs of Asselian to Artinskian age In the Netherland onshore and offshore areas. See Vai & Venturini (this volume) for legend.

GEODIVERSITAS • 1997 • 19(2) 233

Geluk M.

Netherlands are represented only in small areas of the Netherlands by sediments. The deposits of this interval are most l ikely represented by the Lower Rotliegend volcanoclastics. These volca-noclastics occur in two separate areas, namely in the Ems Low in the eastern Netherlands onshore area and the Central North Sea Graben in the offshore area (Fig. 3 ) . Volcanic activity in the Netherlands and Germany occurred in response to wrench movements along Variscan fault zones (Ziegler 1990).

The volcanoclastics in the Ems Low represent the western outliers of a more extensive area of volcanic activity in Germany (Plein 1995). The volcanoclastics consist of red-brown to green spi-litic, basaltic volcanics and mudstones. Several stacked lava flows occur in the succession. The thickness of the volcanics reaches a maximum of 80 m. The age remains speculative, but, based on indi rec t ev idence , is assumed to be Assel ian (Plein 1995).

In the Central North Sea Graben the sequence reaches a thickness of almost 150 m. The volca­nics consist here of massive tuffs and lavas up to several tens of meters thick, interbedded with c l ays tones and s u b o r d i n a t e s ands tones . No reliable datings are available for these volcanics (Ple in 1 9 9 5 ) . T h e y are a s sumed to have an Asselian age. Following the Asselian, a long period of non-deposition followed; sedimention was only resu­med during the youngest stage of the Permian, the Tatarian.

REFERENCES

Lippolt H. J . , Hess J . C. & Burger K. 1984. — Isotopische Alter von pyroklastischen Sanidien aus Kaolin-Kohlentonsteine aus Korrelationmarken fur das mitteleuropaische Oberkarbon. Fortschritte in der Geologie von Rheinland und Westfalen 32: 119-150.

Paproth E., Dusar M., Bless M. J . M., Boukaert J . , Delmer A., Fairon-Demaret M., Houleberghs É., Laloux M., Pierart P., Somers Y., Streel M., Thorez J. & Tricot J. 1983. — Bio- and lithostratigraphic sub­division of the Silesian in Belgium - a review. Annales de la Société géologique de Belgique 106: 241 -283.

Plein E. 1995. — Norddeutsches Rotliegend-becken; Rotliegend-Monographie Teil II, in Plein E. (ed.), Strat igraphie von Deutschland I, Courier Forschungs-Institut Senckenberg 183, 193 p.

Seiter V. 1990. — Sedimentologie und Klimaentwick­lung im Westfal CID und Stephan des nordwestdeut­schen Oberkarbon-Beckens. DGMK-Bericht 384-4, Hamburg, 311p.

Tantow M. S. 1993. — Stratigraphie und seismisches Erscheinungsbild des Oberkarbons (Westfal, Stefan), Emsland. Berliner Geowissenschaften Abhandlungen 148: 66 p.

Van Adrichem Boogaert H. A. & Kouwe W. F. P. 1993-1996. — Stratigraphie nomenclature of the Netherlands, revision and update by RGD and NOGEPA. Mededelingen Rijks Geologische Dienst 50.

Van der Zwan C. J . , van de Laar J . G. M., Pagnier H. J . M. & van Amerom H. W. J . 1993. — Palynological, ecological and climatological synthe­sis of the Upper Carboniferous of the well De Lutte-6 (eastern Netherlands). Comptes Rendus XII ICC-P, Buenos Aires, volume 1 : 167-186

Ziegler P. A. 1990. — Geological atlas of western and central Europe; second and completely revised edition. Shell Internationale Petroleum Maatschappij, The Hague, 239 p.

Submitted for publication on 5 April 1996; accepted on 21 October 1996.

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